Sauer Annette J, Fritsch Eva, Undorf-Spahn Karin, Nguyen Petr, Marec Frantisek, Heckel David G, Jehle Johannes A
Institute for Biological Control, Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Darmstadt, Germany.
Biology Centre of the Czech Academy of Sciences, Institute of Entomology, České Budějovice, Czech Republic.
PLoS One. 2017 Jun 22;12(6):e0179157. doi: 10.1371/journal.pone.0179157. eCollection 2017.
Commercial Cydia pomonella granulovirus (CpGV) products have been successfully applied to control codling moth (CM) in organic and integrated fruit production for more than 30 years. Since 2005, resistance against the widely used isolate CpGV-M has been reported from different countries in Europe. The inheritance of this so-called type I resistance is dominant and linked to the Z chromosome. Recently, a second form (type II) of CpGV resistance in CM was reported from a field population (NRW-WE) in Germany. Type II resistance confers reduced susceptibility not only to CpGV-M but to most known CpGV isolates and it does not follow the previously described Z-linked inheritance of type I resistance. To further analyze type II resistance, two CM strains, termed CpR5M and CpR5S, were generated from parental NRW-WE by repeated mass crosses and selection using the two isolates CpGV-M and CpGV-S, respectively. Both CpR5M and CpR5S were considered to be genetically homogeneous for the presence of the resistance allele(s). By crossing and backcrossing experiments with a susceptible CM strain, followed by resistance testing of the offspring, an autosomal dominant inheritance of resistance was elucidated. In addition, cross-resistance to CpGV-M and CpGV-S was detected in both strains, CpR5M and CpR5S. To test the hypothesis that the autosomal inheritance of type II resistance was caused by a large interchromosomal rearrangement involving the Z chromosome, making type I resistance appear to be autosomal in these strains; fluorescence in situ hybridization with bacterial artificial chromosome probes (BAC-FISH) was used to physically map the Z chromosomes of different CM strains. Conserved synteny of the Z-linked genes in CpR5M and other CM strains rejects this hypothesis and argues for a novel genetic and functional mode of resistance in CM populations with type II resistance.
商业性苹果蠹蛾颗粒体病毒（CpGV）产品已成功应用于有机和综合水果生产中防治苹果蠹蛾（CM）30多年。自2005年以来，欧洲不同国家已报告了对广泛使用的分离株CpGV-M的抗性。这种所谓的I型抗性的遗传是显性的，且与Z染色体连锁。最近，德国一个田间种群（NRW-WE）报告了CM中第二种形式（II型）的CpGV抗性。II型抗性不仅使对CpGV-M的敏感性降低，而且对大多数已知的CpGV分离株也有降低，并且它不遵循先前描述的I型抗性的Z连锁遗传。为了进一步分析II型抗性，通过分别使用分离株CpGV-M和CpGV-S进行反复的大量杂交和选择，从亲本NRW-WE中产生了两个CM品系，称为CpR5M和CpR5S。由于存在抗性等位基因，CpR5M和CpR5S都被认为是基因同质的。通过与敏感CM品系进行杂交和回交实验，然后对后代进行抗性测试，阐明了抗性的常染色体显性遗传。此外，在CpR5M和CpR5S这两个品系中都检测到了对CpGV-M和CpGV-S的交叉抗性。为了检验II型抗性的常染色体遗传是由涉及Z染色体的大型染色体间重排引起的这一假设，使得I型抗性在这些品系中看似为常染色体遗传；使用细菌人工染色体探针的荧光原位杂交（BAC-FISH）来对不同CM品系的Z染色体进行物理定位。CpR5M和其他CM品系中Z连锁基因的保守同线性否定了这一假设，并支持了具有II型抗性的CM种群中存在一种新的抗性遗传和功能模式。
